Folklore, Brewing, and Science

I recently came across a piece of brewing folklore that I found quite interesting. Allegedly, when Norse families would brew beer, they had special sticks that they used to stir the wort. They ascribed magical powers to the stirring sticks, as using the family’s stirring stick would ensure that the beer would turn out well. The stirring sticks were thus treated as family heirlooms.

With the hindsight of a couple hundred years of progress in microbiology, we have a scientific explanation for what was going on: the stirring sticks harbored a colony of yeast that inoculated the wort, ensuring that a desirable fermentation occurred.  This method of action, however, was (presumably) completely unknown to the Norsemen. Nonetheless, their method worked. They identified the pattern that using the same stirring stick over and over yielded better beer, developed a theory for the method of action (magic), and as a result had consistent beer.

Although I can’t find a good reference for this piece of folklore (see herehere and here), I think the story is an interesting parable for scientific discovery. Brewers knew how to successfully make beer centuries before a “scientific” explanation of their methods was discovered. But surprisingly little has changed in how beer is actually brewed. Our understanding of the biology and chemistry of brewing has allowed us more control over the finished product, yet the basics of brewing are essentially the techniques discovered over two millennia of trial and error.

In a sense, the scientific method is little more than an explicit protocol for how to use the trial–and–error method effectively. We observe some physical phenomena, guess at a method of action (or theory), deduce from that theory some predicted phenomena, then check if we observe the predicted the phenomena. By iterating this process and refining our hypotheses, we tend to end up with theories that explain a lot of observable phenomena. In this sense, the scientific method is extraordinarily pragmatic.

The scientific method is, I believe, limited in that it does not tell us *why *nature behaves as it does. There is no reason to believe that a formal theory has any relationship to reality except by analogy — a theoretical prediction corresponds to an experimental measurement. The relative merits of competing theories must be judged on a pragmatic basis. The modern science of zymurgy offers a theoretical framework which gives a brewer great control over their beer. However, whether one ascribes a successful brew to magic, cavorting wee beasties or complex chemical reactions, the methods of brewing don’t seem to be altered in a fundamental way. It seems to me that in many ways, science has changed the way we conceive of brewing more than the way we brew.

Update I realized after reading over this post that it came off as being too critical of science. That wasn’t really my intention in writing the post. Instead, I just wanted to point out that humans tend to be pretty good at recognizing patterns even if we have no clue what the mechanism behind the pattern is. The advantage of the scientific method is that it gives a hypothetical mechanism that accounts for the observed pattern. The hypothetical mechanism may also elucidate other patterns that were not so apparent on their own. In the context of brewing, the mechanism is fermentation by yeast. So in order to ensure a good brew, I should do everything in my power to keep the (good) yeast happy while trying to stifle their competition. Thus science suggests I should sanitize my equipment before putting chilled wort into it, I should make sure the yeast have the nutrients they need to thrive, and I should inoculate the wort with a strain of yeast I know will give good results. My only recourse if I adhere to the “magic stick” mechanism of brewing is to stir and pray. Certainly I would never suggest this as the most viable way to get a consistent brew.

I think the point I was trying to make towards the end of the post is that science only gives a hypothetical mechanism of action that is, a priori, no better than any other explanation of the pattern. The crucial feature of a scientific hypothesis is that it can be disproved: if I hypothesize that yeast turn wort into beer, then you could disprove my hypothesis by showing that some wort turned to beer and throughout the process no yeast were present.

Nonetheless, I want to draw a distinction between theorized mechanisms of action and what might be called physical mechanisms (i.e., the way nature actually works). The difference between these views is that of cause and effect, correlation and causality. Nature doesn’t obey Newton’s (or anyone else’s) laws because these laws accurately describe the way nature works; rather Newton’s laws exist in their present formulation because they accurately predict patterns we see in nature. But that doesn’t mean that competing theories could not be just as successful or that the formalism in which Newton’s laws are expressed has any bearing on why nature behaves as she does. The reason that I think it may be worth belaboring this distinction is that if we only view nature through the lens of some formalism (like classical mechanics, quantum mechanics or general relativity) we potentially miss out on other completely different ways of describing nature that could ultimately be fruitful. I think this idea is implicit (if not explicit) in, for example, Wolfram’s tome A New Kind of Science, although that book is mired in controversy for other reasons.

Ultimately, my point is this: just because a physical theory has been immensely successful in predicting physical phenomena does not mean that it is “correct” in any philosophical or metaphysical sense. More pragmatically, two competing theories can be theoretically incompatible with one another yet still give good (perhaps complimentary) predictions about how nature behaves, so it may be worthwhile to support seemingly contradictory theories. To end with a trite cliche, perhaps it is best if we don’t put all of our eggs into one (theoretical) basket.

Will Rosenbaum

Tel Aviv

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